ESL systems typically include a plurality of ESLs for each merchandise item in a store. ESLs display the price of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. A store may contain thousands of ESLs to display the prices of the merchandise items. The ESLs are coupled to a central server where information about the ESLs is typically maintained in an ESL data file which contains ESL identification information and ESL merchandise item information. The central server sends messages, including register update messages, to the ESLs.
From the perspective of various software components operating on the central server, communication between ESLs and the central server is performed in an asynchronous manner due to the uncertainty of when a response from an ESL will be received and processed. In one prior art ESL system, the processing of the responses occurred by one software component constantly polling another software component to determine if a particular ESL transaction was complete. Such an approach results in unnecessary processing overhead and inefficiencies as a large number of polls would typically occur before the response is available. Therefore, it would be desirable to provide an ESL system and method that provides for an event notification for processing asynchronous ESL transactions.